The goal of this research is to better understand the metabolic state of cells that are deprived of oxygen. In this initial pilot project phase we will adapt methods for analyzing metabolism energetics and oxidative damage to studying the model organism zebrafish (Danio rerio). We will apply these methods; 1. To determine the response of the metabolism and intracellular energetics of zebrafish embryos to varying oxygen tensions at different periods in development. 2. To define the extent of oxidative damage that results from alterations in the oxygen levels. 3. To develop and begin to test hypotheses about mechanisms of surviving hypoxia that may be common to zebrafish and tumors.